Spirostanol Sapogenins and Saponins from Convallaria majalis L. Structural Characterization by 2D NMR, Theoretical GIAO DFT Calculations and Molecular Modeling

Abstract

Two new spirostanol sapogenins (5β-spirost-25(27)-en-1β,2β,3β,5β-tetrol 3 and its 25,27-dihydro derivative, (25S)-spirostan-1β,2β,3β,5β-tetrol 4) and four new saponins were isolated from the roots and rhizomes of Convallaria majalis L. together with known sapogenins (isolated from Liliaceae): 5β-spirost-25(27)-en-1β,3β-diol 1, (25S)-spirostan-1β,3β-diol 2, 5β-spirost-25(27)-en-1β,3β,4β,5β-tetrol 5, (25S)-spirostan-1β,3β,4β,5β-tetrol 6, 5β-spirost-25(27)-en-1β,2β,3β,4β,5β-pentol 7 and (25S)-spirostan-1β,2β,3β,4β,5β-pentol 8. New steroidal saponins were found to be pentahydroxy 5-O-glycosides; 5β-spirost-25(27)-en-1β,2β,3β,4β,5β-pentol 5-O-β-galactopyranoside 9, 5β-spirost-25(27)-en-1β,2β,3β,4β,5β-pentol 5-O-β-arabinonoside 11, 5β-(25S)-spirostan-1β,2β,3β,4β,5β-pentol 5-O-galactoside 10 and 5β-(25S)-spirostan-1β,2β,3β,4β,5β-pentol 5-O-arabinoside 12 were isolated for the first time. The structures of those compounds were determined by NMR spectroscopy, including 2D COSY, HMBC, HSQC, NOESY, ROESY experiments, theoretical calculations of shielding constants by GIAO DFT, and mass spectrometry (FAB/LSI HR MS). An attempt was made to test biological activity, particularly as potential chemotherapeutic agents, using in silico methods. A set of 12 compounds was docked to the PDB structures of HER2 receptor and tubulin. The results indicated that diols have a higher affinity to the analyzed targets than tetrols and pentols. Two compounds (25S)-spirosten-1β,3β-diol 1 and 5β-spirost-25(27)-en-1β,2β,3β,4β,5β-pentol 5-O-galactoside 9 were selected for further evaluation of biological activity.

In vitro antidermatophytic activity of bioactive compounds from selected medicinal plants

“…The antidermatophytic activity of spirostanol saponin isolated from A. racemosus cladode in our study is similar to other findings. Antimycotic activity of spirostanol saponins has been reported in Solanum hispidum leaves (Manases González et al 2004 ; Diretto et al 2017 ; El Sayed et al 2020 ; Dąbrowska-Balcerzak et al 2021 ). Therefore, this plant saponin has great potential to bolster the antifungal armamentarium for treatment of fungal infections that does not respond to conventional therapy.…”

Fenugreek derived diosgenin as an emerging source for diabetic therapy

“…It also contains a double bond at 5,6 position and has an R configuration at position 25. It has a hydroxyl group in the third position; hydroxyl groups are typically found in combination with sugars, making the compounds water-soluble and highly saponaceous (51). In aqueous medium, it has a solubility of about 0.7 • ng/ml.…”

Nuclear Magnetic Resonance

“…Structure and NMR properties of spirostanol sapogenins and saponins from Convallaria majalis l. were studied experimentally and theoretically. 102 6 Nuclear shielding studies for solids Modeling nuclear shielding tensor in solids is very useful in studies of novel materials and in pharmacy. Obviously, intermolecular interactions are not considered in case of single molecule in the gas phase, serving as a very approximate model of solids (without inclusion of periodicity in crystals).…”